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Error Analysis of Liquid Holdup Measurement in Gas-Liquid Annular flow Through Circular Pipes Using High-Speed Camera Method

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Journal of Shanghai Jiaotong university(Science) 2018年第S1期23卷 34-40页

作者： LIU Li BAI Bofeng School of Nuclear Science and Engineering Shanghai Jiao Tong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

Accurate measurement of gas-liquid phase fraction is essential for the proper modelling of the pressure drop, heat transfer coefficient, mass transfer rate and interfacial area in two-phase flows. In this paper, taking the issue of optical distortion into account, an analytical model was proposed to estimate and correct the liquid holdup in gas-liquid annular flow through a circular pipe using high-speed camera method. The error in the liquid holdup measurement generated from different refractive indices among transparent circular pipe, liquid film and air core was firstly theoretically analyzed based on the geometric optics. Experimental tests were then carried out to identify the difference as well as to validate the proposed model. Results indicated that the prediction of the liquid holdup has a good performance with the experimental data(i.e., mean relative error is 4.1%) and the measured liquid holdup is larger than the real one. It was found that the measured liquid holdup is larger than the real one. Generally, when the real liquid holdup gets smaller, the discrepancy between the measured liquid holdup by image and the real liquid holdup becomes more significant. Thus, after measuring the liquid holdup from the images, the value of the measured liquid holdup must be corrected by the present model in order to obtain the real liquid holdup.

关键词： gas-liquid annular flow liquid holdup optical refraction analytical correction

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Experimental Study on Condensation Heat Transfer Characteristics inside an Inclined Wave-Finned Flat Tube of Direct Air-Cooling System

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Journal of Thermal Science 2021年第2期30卷 432-440页

作者： WANG Haitao TAO Tao MEI Xuesong WANG Haijun GU Hongfang State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong UniversityXi'an 710049China Shaanxi Key Laboratory of Intelligent Robots School of Mechanical EngineeringXi'an Jiaotong UniversityXi'an 710049China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

In this paper,the condensation heat transfer characteristics of parallel flow and counter flow inside an inclined wave-finned flat tube is investigated *** condensation heat transfer coefficients are analyzed based on the experimental *** of experiments show that condensation heat transfer coefficient decreases as the temperature difference Δt=ts-tw increases and mass flow rate *** parallel flow has a similar development with the counter flow,and the condensation heat transfer coefficient of counter flow is less than that of parallel flow under the same air cooling *** addition,condensation heat transfer coefficient correlations are also obtained under experimental *** calculations agree well with the measured data and the agreement is seen to be within ±4% for the parallel flow and ±5% for the counter flow.

关键词： condensation heat transfer wave-finned fiat tube modified model parallel flow counter flow

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A two-stage reduction process for the production of high-purity ultrafine Ni particles in a micro-fluidized bed reactor

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Particuology 2015年第2期13卷 27-34页

作者： Jun Li Xinwei Liu Li Zhou Qingshan Zhu Hongzhong Li State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of Sciences

A novel two-stage reduction process for synthesis of ultrafine nickel powder with a high purity and low density in a fluidized bed reactor has been developed in this work. The raw ultraflne NiO particles are first pre-reduced using hydrogen at lower temperatures （340-400 ℃）, followed by further reduction at higher temperatures （500-600℃）. The self-agglomeration of Ni particles formed during low-temperature reduction decreases the sintering activity of the newly formed ultrafine Ni particles, leading to good fluidization quality, even for the subsequent high-temperature reduction process. The agglomerated Ni particles have a high Ni content （above 99wt%）, a low density （0.78g/cm^3） and a uniform particle size （approximately 100 μm）. A concept design for a novel two-stage fluidized bed reactor process used to produce high-purity Ni powder was also proposed. This approach may be extended to the synthesis of other ultrafine/nanosized metals or metal oxides through a fluidization method.

关键词： Ultrafine Ni powder Production Fluidized bed reactor Two-stage reduction

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Design and synthesis of porous non-noble metal oxides for catalytic removal of VOCs

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Science China Chemistry 2015年第9期58卷 1359-1366页

作者： Wenxiang Tang Gang Liu Dongyan Li Haidi Liu Xiaofeng Wu Ning Han Yunfa Chen State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences

The design and synthesis of highly active non-noble metal oxide catalysts, such as transition- and rare-earth-metal oxides, have attracted significant attention because of their high efficiency and low cost and the resultant potential applications for the degradation of volatile organic compounds(VOCs). The structure-activity relationships have been well-studied and used to facilitate design of the structure and composition of highly active catalysts. Recently, non-noble metal oxides with porous structures have been used as catalysts for deep oxidation of VOCs, such as aromatic hydrocarbons, aliphatic compounds, aldehydes, and alcohols, with comparable activities to their noble metal counterparts. This review summarizes the growing literature regarding the use of porous metal oxides for the catalytic removal of VOCs, with emphasis on design of the composition and structure and typical synthetic technologies.

关键词： VOCs catalytic oxidation non-noble metal oxides structure-activity relationships synthetic methods

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Cobalt oxide and carbon modified hematite nanorod arrays for improved photoelectrochemical water splitting

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Chinese Chemical Letters 2017年第12期28卷 2207-2211页

作者： Miao Wang Meng Wang Yanming Fu Shaohua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an fiaotong UniversityXi'on 710049China

Given the proper band gap, low cost and good stability, hematite （α-Fe2O3） has been considered as a promising candidate for photoelectrochemical （PEC） water splitting, however suffers from the sluggish surface water oxidation reaction kinetics. In this study, a simple dip-coating process was used to modify the surface of α-Fe2O3 nanorod arrays with cobalt oxide （COOx） and carbon （C） for the improved PEC performance, with a photocurrent density at 1.6V （vs. reversible hydrogen electrode, RHE） increased from 0.10 mA/cm2 for the pristine α-Fe2O3 to 0.37 mA/cm2 for the CoOx/C modified α-Fe2O3 nanorods. As revealed by electrochemical analysis, thanks to the synergistic effect of CoOx and C, the PEC enhancement could be attributed to the enhanced charge transfer ability, decreased surface charge recombination, and accelerated water oxidation reaction kinetics. This study serves as a good example for improving PEC water splitting performance via a simple method.

关键词： Hematite nanorodsSurface modificationPhotoelectrochemical water splittingWater oxidationElectrochemical impedance spectroscopy

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An investigation into the heat transfer characteristics of spiral wall with internal rib in a supercritical sliding-pressure operation once-through boiler

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中国高等学校学术文摘·能源与动力工程 2007年第3期1卷 300-304页

作者： TANG Renhu YIN Fei WANG Haijun CHEN Tingkuan The State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

Within the pressure range of 9-28 MPa,mass 200-500 kW/m2,experiments were performed to investigate the heat transfer to water in the inclined upward internally ribbed tube with an inclined angle of 19.5 degrees,a maximum outer diameter of 38.1 mm,and a thickness of 7.5 *** on the experiments,it was found that heat transfer enhancement of the internally ribbed tube could postpone departure from nucleate boiling at the sub-critical ***,the heat transfer enhancement decreased near the critical *** supercritical pressure,the temperature difference between the wall and the fluid increased near the pseudo-critical temperature,but the increase of wall temperature was less than that of departure from nucleate boiling at sub-critical *** pressure is closer to the critical pressure,the temperature difference between the wall and the fluid increased greatly near the pseudo-critical *** transfer to supercritical water in the inclined upward internally ribbed tube was enhanced or deteriorated near the pseudo-critical temperature with the variety of ratio between the mass velocity and the heat *** the rotational flow of the internal groove reduced the effect of natural convection,the internal wall temperature of internally ribbed tube uniformly distributed along the *** maximum internal wall temperature difference of the tube along the circumference was only 10 degrees when the fluid enthalpy exceeded 2 000 J/*** the effect of acute variety of the fluid property on heat transfer,the correlation of heat transfer coefficient on the top of the internally ribbed tube was orovided.

关键词： thermal power engineering heat transfer supercritical pressure boiler internally ribbed tube departure from nucleate boiling

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Numerical and experimental research of the characteristics of concentration solar cells

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Frontiers in Energy 2021年第2期15卷 279-291页

作者： Zilong WANG Hua ZHANG Binlin DOU Weidong WU Guanhua ZHANG Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power EngineeringUniversity of Shanghai for Science and TechnologyShanghai 200093China

The development of automatic tracking solar concentrator photovoltaic systems is currently attracting growing *** concentration photovoltaic systems(HCPVs)combining triple-junction InGaP/lnGaAs/Ge solar cells with a concentrator provide high conversion *** mathematical model for triple-junction solar cells,having a higher efficiency and superior temperature characteristics,was established based on the one-diode equivalent circuit cell model.A paraboloidal concentrator with a secondary optic system and a concentration ratio in the range of 100X–150X along with a sun tracking system was developed in this *** GaInP/GalnAs/Ge triple-junction solar cell,produced by AZUR SPACE Solar Power,was also used in this *** solar cells produced by Shanghai Solar Youth Energy(SY)and Shenzhen Yinshengsheng Technology ***.(YXS)were used as comparison samples in a further comparative study at different concentration ratios(200X–1000X).A detailed analysis on the factors that influence the electrical output characteristics of the InGaP/lnGaAs/Ge solar cell was conducted with a dish-style concentrating photovoltaic *** results show that the short-circuit current(Isc)and the open-circuit voltage(Voc)of multi-junction solar cells increases with the increasing concentration ratio,while the cell efficiency(ηc)of the solar cells increases first and then decreases with increasing concentration *** increasing solar cell temperature,Isc increases,while Voc andηc decrease.A comparison of the experimental and simulation results indicate that the maximum root mean square error is less than 10%,which provides a certain theoretical basis for the study of the characteristics of triple-junction solar cell that can be applied in the analysis and discussion regarding the influence of the relevant parameters on the performance of high concentration photovoltaic systems.

关键词： concentration three-junction solar cell mathematical model electrical properties solar energy

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Proposal and thermodynamic analysis of a steam methane reforming system integrated with thermochemical energy storage and a SCO2 brayton cycle

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Journal of Energy Storage 2025年 127卷

作者： Fu, Yu Liu, Ming Wang, Zhu Xie, Tao Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Institute of Industrial Catalysis School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an710049 China

Solar energy is a promising alternative to fossil fuels for providing heat in steam methane reforming (SMR) hydrogen production. However, the variability of solar energy requires effective storage solutions. This study presents a new SMR hydrogen production system that integrates thermochemical energy storage (TCES) utilizing a CaO/CaCO3 cycle with a SCO2 Brayton cycle. The system converts fluctuating solar energy into the stable chemical energy of CaO by calcinating CaCO3 in the solar calciner, with the SMR reaction mainly heated by the exothermic reaction of CaO and CO2. The SCO₂ Brayton cycle efficiently recovers heat from the high-temperature SMR products. Comprehensive thermodynamic analysis and evaluation models are developed. Results show that the proposed system performs well, achieving energy and exergy efficiencies of 73.49 % and 78.46 %, respectively, under benchmark conditions. The energy storage efficiency of TCES is 81.55 %, and the solar-to-chemical energy efficiency is 48.21 %. Integrating TCES significantly enhances the system's steady operation under fluctuating solar energy conditions. The calciner accounts for the largest share of exergy destruction at 31.63 %, followed by the carbonator at 17.50 %. Sensitive analyses of key operating parameters indicate that higher CaO conversion rate and storage temperature enhance energy storage, energy, and exergy efficiencies. Besides, the energy and exergy efficiencies decrease with the increasing SMR reaction pressure but increase with rising reaction temperature. When the S/C is 2.0, these efficiencies reach their maximum values of 75.42 % and 78.63 %, respectively. © 2025 Elsevier Ltd

关键词： Brayton cycle

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Best estimate plus uncertainty analysis of the China advanced large-scale PWR during LBLOCA scenarios

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International Journal of Advanced Nuclear Reactor Design and Technology 2020年 2卷 34-42页

作者： Chang, Yuhao Wang, Mingjun Zhang, Jing Tian, Wenxi Qiu, Suizheng Su, G.H. Department of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

China advanced large-scale Pressurized Water Reactor (PWR) implements series of passive safety systems to provide core cooling and decay heat removal in case of some unexpected accidents. The development of reactor best estimate system analysis codes has realized the transition from conservative safety analysis to Best Estimate plus Uncertainty (BEPU) analysis for the purpose of achieving more realistic results and digging larger safety margins. The BEPU analysis during Large Break Loss of Coolant Accident (LBLOCA) has been widely used for the licensing application of Nuclear Power Plants (NPPs). In this paper, the BEPU analysis of China advanced large-scale PWR was performed under the conditions of LBLOCA scenarios employing RELAP5 code. The models of reactor coolant system with all the passive safety systems were established and the influence of uncertainties of important parameters on the Peak Cladding Temperature (PCT) was evaluated. The results show the obtained PTC (1314 K) through the BEPU analysis is far below the 10CFR50.46 PCT acceptance criteria (1477 K) in case of LBLOCA and is also lower than the conservative calculation value (1348 K), indicating a larger safety margin. This work provides a meaningful evaluation method for China advanced large-scale PWR safety assessment. © 2020 Xi'an Jiaotong University

关键词： Pressurized water reactors

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Simulation of horizontal slug-flow pneumatic conveying with kinetic theory

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中国高等学校学术文摘·能源与动力工程 2007年第3期1卷 336-340页

作者： GU Zhengmeng GUO Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

Wavelike slug-flow is a representative flow type in horizontal pneumatic *** theory was introduced to establish a 3D kinetic numerical model for wavelike slug gas-solid flow in this *** motion of particulate slugs in horizontal pipes was numerically *** formation and motion process of slugs and settled layer were *** characteristics of the flow,such as pressure drop,air velocity distribution,slug length and settled layer thickness,and the detailed changing characteristics of slug length and settled layer thickness with air velocity were *** results indicate that kinetic theory can represent the physical characteristics of the non-suspension dense phase flow of wavelike slug pneumatic *** experiment in this paper introduced a new idea for the numerical calculation of slug-flow pneumatic conveying.

关键词： slug-flow pneumatic conveying kinetic theory simulation

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